# -*- coding: utf-8 -*-
"""
    sphinx.builders.devhelp
    ~~~~~~~~~~~~~~~~~~~~~~~

    Build HTML documentation and Devhelp_ support files.

    .. _Devhelp: https://wiki.gnome.org/Apps/Devhelp

    :copyright: Copyright 2007-2018 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""
from __future__ import absolute_import

import gzip
import re
from os import path
from typing import Any

from docutils import nodes

from sphinx import addnodes
from sphinx.builders.html import StandaloneHTMLBuilder
from sphinx.environment.adapters.indexentries import IndexEntries
from sphinx.locale import __
from sphinx.util import logging
from sphinx.util.nodes import NodeMatcher
from sphinx.util.osutil import make_filename

try:
    import xml.etree.ElementTree as etree
except ImportError:
    import lxml.etree as etree  # type: ignore

if False:
    # For type annotation
    from typing import Dict, List  # NOQA
    from sphinx.application import Sphinx  # NOQA


logger = logging.getLogger(__name__)


class DevhelpBuilder(StandaloneHTMLBuilder):
    """
    Builder that also outputs GNOME Devhelp file.
    """
    name = 'devhelp'
    epilog = __('To view the help file:\n'
                '$ mkdir -p $HOME/.local/share/devhelp/books\n'
                '$ ln -s $PWD/%(outdir)s $HOME/.local/share/devhelp/books/%(project)s\n'
                '$ devhelp')

    # don't copy the reST source
    copysource = False
    supported_image_types = ['image/png', 'image/gif', 'image/jpeg']

    # don't add links
    add_permalinks = False
    # don't add sidebar etc.
    embedded = True

    def init(self):
        # type: () -> None
        StandaloneHTMLBuilder.init(self)
        self.out_suffix = '.html'
        self.link_suffix = '.html'

    def handle_finish(self):
        # type: () -> None
        self.build_devhelp(self.outdir, self.config.devhelp_basename)

    def build_devhelp(self, outdir, outname):
        # type: (unicode, unicode) -> None
        logger.info(__('dumping devhelp index...'))

        # Basic info
        root = etree.Element('book',
                             title=self.config.html_title,
                             name=self.config.project,
                             link="index.html",
                             version=self.config.version)
        tree = etree.ElementTree(root)

        # TOC
        chapters = etree.SubElement(root, 'chapters')

        tocdoc = self.env.get_and_resolve_doctree(
            self.config.master_doc, self, prune_toctrees=False)

        def write_toc(node, parent):
            # type: (nodes.Node, nodes.Node) -> None
            if isinstance(node, addnodes.compact_paragraph) or \
               isinstance(node, nodes.bullet_list):
                for subnode in node:
                    write_toc(subnode, parent)
            elif isinstance(node, nodes.list_item):
                item = etree.SubElement(parent, 'sub')
                for subnode in node:
                    write_toc(subnode, item)
            elif isinstance(node, nodes.reference):
                parent.attrib['link'] = node['refuri']
                parent.attrib['name'] = node.astext()

        matcher = NodeMatcher(addnodes.compact_paragraph, toctree=Any)
        for node in tocdoc.traverse(matcher):
            write_toc(node, chapters)

        # Index
        functions = etree.SubElement(root, 'functions')
        index = IndexEntries(self.env).create_index(self)

        def write_index(title, refs, subitems):
            # type: (unicode, List[Any], Any) -> None
            if len(refs) == 0:
                pass
            elif len(refs) == 1:
                etree.SubElement(functions, 'function',
                                 name=title, link=refs[0][1])
            else:
                for i, ref in enumerate(refs):
                    etree.SubElement(functions, 'function',
                                     name="[%d] %s" % (i, title),
                                     link=ref[1])

            if subitems:
                parent_title = re.sub(r'\s*\(.*\)\s*$', '', title)
                for subitem in subitems:
                    write_index("%s %s" % (parent_title, subitem[0]),
                                subitem[1], [])

        for (key, group) in index:
            for title, (refs, subitems, key) in group:
                write_index(title, refs, subitems)

        # Dump the XML file
        xmlfile = path.join(outdir, outname + '.devhelp.gz')
        with gzip.open(xmlfile, 'w') as f:  # type: ignore
            tree.write(f, 'utf-8')


def setup(app):
    # type: (Sphinx) -> Dict[unicode, Any]
    app.setup_extension('sphinx.builders.html')
    app.add_builder(DevhelpBuilder)

    app.add_config_value('devhelp_basename', lambda self: make_filename(self.project), None)

    return {
        'version': 'builtin',
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }
